The present invention relates to a service switching means for a mobile integrated intelligent network and further to a service control means for such a mobile integrated intelligent network.
In particular, the present invention relates to a mobile integrated intelligent network wherein the service switching means interacts with a local service control means in the event of international roaming.
Recently, a standard called EIRENE was created by a group of European railway operators in order to specify and standardize a pan-European universal railway communication system as private networks or virtual private networks with the intention to satisfy all operative railway communication means on a single mobile cellular network platform, e.g., the GSM platform.
A vital part of railway communication relates to a functional numbering and functional number registration. Here, the concept of functional numbers is introduced with the intention of releasing railway operative personnel of having to resort to temporary look-up tables when they want to contact a train currently roaming in the related railway operation range. Heretofore, there is specified a numbering plan based on train numbers and other running stock numbers. Typically, the mobile station number MSISDN assigned to a train driver is registered in relation to the train number he is currently driving.
FIG. 7 shows the concept of a gateway node initially introduced. In particular, it was proposed that a gateway node 100 would take over the task to translate the functional number supplied by a switch 102 into the actual routable mobile station number MSISDN of the destination. Thus, using the concept of a gateway node a call is routed to this gateway node 100 wherein a number of translations takes place to achieve a certain service. However, the use of such a gateway node arrangement quickly became obsolete due to various reasons including extra hardware costs and transmission costs.
An alternative to the concept of a gateway node relies on the implementation of mobile integrated intelligent networks, as will be shown in the following.
FIG. 8 shows a schematic diagram according to the general architecture of intelligent network communication systems. As shown in FIG. 8, there is provided a service control point 104 to control the switching of messages in the intelligent network communication system. Further, there are provided service switching functions 106 triggering calls/messages and invoking a re-routing of calls and messages to the service control point 104 for analysis.
As also shown in FIG. 8, the service switching function 106 is linked to an intelligent peripheral 108 or equivalently a terminal unit which implements specialized functions required for intelligent network communication services. The service control point 104 may also be linked to a service administration system 110 that provides the design environment for the creation of service logic.
During operation after a message has been triggered in the service switching function 106 a request for instructions is sent from the service switching function 106 to the service control point 104. Then, the service control point 104 performs service control in response to the request with instructions back to the service switching function 106 forwarding the service to the intelligent peripheral 108.
The general architecture of the intelligent network concept IN is, e.g., defined by ITU-TS in the recommendation Q.1204. While in the following, the functional entities are only described as far as the present invention is concerned, further details may be taken from references van Hal, P., van der Meer, J. and Salah, N.: xe2x80x9cThe Service Script Interpreter, an Advanced Intelligent Network Platformxe2x80x9d, Ericsson Review 67 (1990): 1, pp. 12-22, Ljungblom, F.: xe2x80x9cA Service Management System for the Intelligent Networkxe2x80x9d, Ericsson Review 67 (1990): 1, pp. 32-41, and Sxc3x6derberg, L.: xe2x80x9cArchitecture for Intelligent Networksxe2x80x9d, Ericsson Review 66 (1989): 1, pp. 13-22 and enclosed herein by reference.
The architecture of the intelligent network shown in FIG. 8 may be integrated into a cellular mobile network, e.g., the GSM cellular mobile network, as explained in the following with respect to FIG. 9.
Typically, each cellular mobile network allows its users to initiate and receive calls and services, respectively, at any geographical area within the radio coverage of the home public land mobile network HPLMN operated by the network operator selected through the subscriber and also within the radio coverage areas of partners of the network operator providing services in visited public land mobile networks VPLMN.
As shown in FIG. 9, a link between different public land mobile networks or to any other network, e.g., the public switched telephone network PSTN is achieved through a gateway mobile services switching center GMSC. This gateway mobile services switching center GMSC is connected to a functional unit called home location register HLR where both, subscriber information and mobile information, are stored to allow incoming calls to be routed to a mobile station MS. To this end, the gateway mobile services switching center GMSC is also connected to a mobile services switching center MSC through which the mobile station MS can receive a service. This mobile service switching center MSC performs the necessary switching functions required for mobile stations MS covered by this particular mobile services switching center MSC.
Heretofore, the mobile service switching center MSC is also connected to a visitor location register VLR that dynamically stores mobile station information, such as the location area in case the mobile station is located in the service area covered by the visitor location register VLR. Therefore, in case a roaming mobile station MS enters this service area, the mobile services switching center MSC informs the associated visitor location register VLR about this roaming mobile station MS.
As is also shown in FIG. 9, to realize the mobile integrated intelligent network the service switching function shown in FIG. 8 may be integrated into the mobile services switching center MSC. Further, the mobile services switching center MSC is interfaced to the service control point 104 to achieve the transparent link between mobility support communication systems, i.e. the intelligent network IN and the mobile cellular network GSM. In other words, the service control point 104 may be implemented as stand-alone node and the service switching function SSF may be integrated into the mobile services switching center MSC.
FIG. 10 shows the impact of the mobile integrated intelligent network shown in FIG. 9 onto the operation of a pan-European universal railway communication system.
As shown in FIG. 10, the current intelligent network functionality relies on a dedicated service control point 114 for each subscriber being located in the home public land mobile network HPLMN of the subscriber. To illustrate the impact of this approach onto the operation of the mobile integrated intelligent network, FIG. 10 shows a typical example where a train is, e.g., roaming from Spain via France to Germany and is currently cruising France.
In such a case, it might be necessary that a traffic controller wishes to contact the personnel on the train via the local mobile cellular network which is a visitor public land mobile network for the cruising train. Typically, the traffic controller interacts with the train driver via a MSC/VLR and the service switching function integrated therein. Thereafter, the service switching function carries out an access to subscriber record storing the address gsmSPC according to the address of the service control point 114 being located in the home public land mobile network, i.e. in Spain. As this service control point 114 executes control over the services supplied to the train driver in France, this would force the railway operators in both countries to coordinate services on a very detailed and international level which would incur both, costs and delays.
In other words, the switching standards for pan-European railway operator communication systems specify a system which is intended to serve completely different purposes when compared to mobile cellular networks. Here, the focus is not on the individual subscribers but on fulfilling the requirements of the railway companies and their operational necessities such as functional numbering. While generally a mobile integrated network has the objective to support HPLMN services to VPLMN to allow the HPLMN operator to offer a homogeneous service to subscriber, railway operators have a different set of priorities. Their goal is to implement a numbering plan for all subscribers roaming locally under their control.
However, as shown in FIG. 11 being related to different protocols for the exchange of data and services in the mobile integrated intelligent network, this is currently not possible since irrespective of the position of a subscriber either in the home or visited public land mobile network each service switching function gsmSCF implemented in the mobile cellular network always interrogates the same service control point gsmSCF in the home public land mobile network via a intelligent network specific protocol such as the CAP (CAMEL application protocol, CAMEL{circumflex over (=)}Customized Application For Mobile Network Enhanced Logic).
Further, FIG. 11 shows the transaction between the different components of the mobile cellular network GSM illustrated in FIG. 9 via the related protocol, i.e. the MAP (mobile application part protocols). In any visited public land mobile network a train controller taking responsibility for this area will never have the possibility to control a train roaming under his control via a dedicated local service control point but must rely on the control executed through a remote service control point located in the home public land mobile network HPLMN.
Using the unchanged intelligent network architecture shown in FIGS. 9 and 11, respectively, running numbers and coach numbers must be administrated European wide in the home public land mobile network. Further, a functional number re-registration for a roaming train registered in each visited public land mobile network is not supported at all. Also, all railway operators must implement the intelligent network standard and provide appropriate services according to different national requirements. Still further, since one used functional number may not be used elsewhere, this causes a problem for an internationally roaming trains running under the same functional number in different countries.
In view of the above, the object of the invention is to provide a mobile integrated intelligent network enabling local control on subscribers roaming in a plurality of public land mobile networks.
According to the present invention, this object is achieved through a service switching means for a mobile integrated intelligent network, comprising interrogation means adapted to receive at least a routable number from a service control means in accordance with a functional number supplied thereto and specifying a subscriber to the mobile integrated intelligent network on a functional level, and an address storage means storing an address of the service control means such that the interrogation is directed to a local service control means in the event of international roaming.
Therefore, the present invention retains to general intelligent networks and standard interfaces, e.g., the CAMEL standard, but introduces a modification of the intelligent network architecture. Instead of interrogating the service control point for internationally roaming subscribers in the home public land mobile network, a local service control point is interrogated. This allows the railway operator to have detailed control over the services of all subscribers in the network, i.e. even with internationally roaming subscribers. In other words, the translation of dialled functional numbers to actual routable numbers is performed locally and also the control of varying services may be handled locally. Here, xe2x80x9clocallyxe2x80x9d means in the same network as the call originator is located in.
According to a preferred embodiment of the present invention, the mobile integrated intelligent network is built on top of the mobile cellular network GSM such that the service switching function is integrated into the related mobile services switching centers MSC. Preferably, the address of the local service control point is stored in the data entry previously pointing to the service control point in the home public land mobile network HPLMN of the subscriber. Therefore, the gsmSCF address that is normally used for the intelligent network is overwritten with the locSCP address which is then used to direct the service control point interrogation to the local service control point. Since a local service control point is interrogated, the railway operator has detailed control over the services provided to the subscribers roaming in his network even in the case of internationally roaming subscribers.
According to further preferred embodiments of the present invention, the overwrite mechanisms are either activated in case subscriber related data is received in the visitor location register or in case call related data is received therein.
Subscriber related data may be data on a lower level such as O-CSI (Originating CAMEL Subscriber Information) data in the context of a call set-up. Further, both overwrite mechanisms may be steered through the IMSI-series of the subscriber, through the A-number, or any other indication defined for this subscriber. After the gmsSCP address is overwritten with the locSCF address, interrogations are performed to the local service control point, however using the standard intelligent network interface, e.g., the CAMEL Application Protocol (=CAP) interface. Therefore, the controlling definition of services is a clearly local issue. Using this mechanism, a very sophisticated selection of the service control point may be realized. This approach even enables the possibility to connect to different local services control point addresses for different subscribers, functional numbers, etc. in dependence on the overwrite mechanism. This allows for a isuitable administration of available capacities and resources.
According to a further aspect of this invention, the object outlined above is achieved through service control means for a mobile integrated intelligent network, comprising an interface means adapted to link the service control means to a mobile services switching center of a mobile cellular network, a service profile handling means adapted to perform service control for each subscriber with dependency on the registered functional number to the mobile integrated intelligent network, and a routing database means adapted to determine a routable number in accordance with a functional number supplied to service control means and specifying a subscriber to the mobile integrated intelligent network on a functional level.
Therefore, according to this further aspect of the invention the explicit re-registration of a roaming train when entering a new visited public land mobile network is clearly supported. In consequence, as soon as the roaming subscriber roams into a new visited public land mobile network also the related local control will be switched to the operator of this new visited public land mobile network.